Work tools, such as shears, grabs, or buckets may be coupled with host machines, such as excavators, to perform work operations like cutting, grabbing or excavating. The work tools may be coupled to a boom or stick mechanism of the host machine via a fixed connection or a quick release connection.
A quick release connection allows for a relatively easy exchange of the work tool whereby the operator may connect or change a work tool without leaving the cab. The machine mounting bracket is arranged to slide into the work tool mounting bracket, when the work tool is positioned on the ground. After aligning the mounting bracket of the work tool and the mounting bracket of the machine, a locking device may be moved into a locked position to lock the work tool to the machine.
When connecting the work tool to the machine, the hydraulic hoses of the machine and work tool pressure fluid circuits may be connected for driving the work tool. Automatic hydraulic hose connection systems are known which may be activated by the operator from the cab for connection of the hydraulic hoses. Such systems may often be dependent on the connection of the work tool to the machine. Hydraulic hose couplers may be provided and arranged so that during connection of the work tool to the machine the hose couplers are also automatically connected. When the work tool mounting bracket is connected to the machine mounting bracket, the hose couplers may be contemporaneously connected.
However, aligning the hose couplers may require a higher level of accuracy than alignment of the mounting brackets. In practice, when a coupling arrangement is provided with such hose couplers, an operator may try to avoid relatively rough movements and high forces that are typical when connecting the work tool to the machine. Such actions may result in loss in efficiency. Nevertheless, a relatively high risk to cause damage to the hydraulic hose couplers remains due to the high forces and potential rough alignments between the mounting brackets. When the hose couplers are not aligned accurately, at connection of the machine and work tool pressure fluid circuits, pressurized fluid may escape or the couplers and/or hoses may need to be changed. As the hydraulic circuits of host machines may operate under relatively high pressures, any leakage may cause major spillage of hydraulic fluid and significant downtime.
EP1388616 discloses a coupling arrangement for coupling two ends of a pressurized hydraulic fluid circuit of a work tool and a machine. The coupling arrangement may comprise a quick release mounting bracket for coupling a work tool to a machine. The coupling arrangement may comprise a receiving fluid coupler and a moving fluid coupler, each coupler being connected to a hydraulic hose of a main hydraulic circuit.
One of the couplers may be arranged on the work tool and the other coupler may be arranged on the machine. Both couplers may be connected to each other for providing a fluid passage between the hydraulic hoses so that pressurised fluid may circulate between the fluid circuit of a work tool and a machine. The moving fluid coupler may be moved on a sledge to and from the receiving fluid coupler by an actuator. When the respective moving coupler is coupled to the receiving coupler, a locking notch may engage the moving coupler to keep both couplers coupled so that the actuator may release its pressure while fluid flows through the couplers. The locking notch requires significant space in the coupling arrangement. Moreover, after multiple engagements, the locking notch may become damaged, or may allow for play to occur which may cause leakage of fluid between the couplers. However, without the locking notch, the actuator would have to withstand significant forces that are exerted by the pressurised fluid flowing through the circuit, which may disengage the couplers. Furthermore, during movement of the coupler, the hydraulic hose that is coupled to the moving coupler may become wedged, caught, or trapped in or between the structure of the machine and/or the work tool.
WO2010062166, in the name of Caterpillar Work Tools B.V., discloses a coupling arrangement for coupling a work tool to a machine. The coupling arrangement may have a locking arrangement for locking the work tool to the machine. The locking arrangement may comprise a locking member which may be moved to a locked position where it abuts the locking member receiving elements.
The coupling arrangement further may have at least two fluid couplers arranged to be connected to each other for establishing a fluid passage between a main pressurized fluid circuit channel of a work tool and a main pressurized fluid circuit channel of a machine. The coupling arrangement may further have a driving arrangement for driving at least one of the fluid couplers for connection to the other fluid coupler, the driving arrangement being separate from the main pressurized fluid circuit.
The present disclosure is directed, at least in part, to improving or overcoming one or more aspects of the prior art system.